Pad roller device for motion-picture projecting machines



Nov. 21, 1950 E. BOECKING 2,530,448

PAD ROLLER DEVICE FOR MOTION-PICTURE PROJECTING MACHINES 4 Sheets-Sheet 1 Filed April 19, 1946 I4 52 A 20 45 1. O

,y n 300 lnvenfor 42 0 30 Ewa/a' Boec/whg BY H/S AZ'TOR/VEYS Nov. 21, 1950 BOECKING 2,530,448

PAD ROLLER DEVICE FOR MOTION-PICTURE PROJECTING MACHINES Filed April 19, 1946 4 Sheets-Sheet 2 lnvenfor Ewe/0 Boec/whg B Y HAS A rromvs Y8 MMM Nov. 21, 1950 E. BOECKING 2,530,443

PAD ROLLER DEVICE FOR MOTION-PICTURE PROJECTING MACHINES Filed April 19, 1946 4 Sheets Sheet s lnvenfor Ewo/a Boechhg BYH/SATTOR/VE Y5 Nov. 21, 1950 E. BOECKING 2,530,448

, PAD ROLLER DEVICE FOR MOTION-PICTURE PROJECTING MACHINES Filed April 19, 1946 4 Sheets-Sheet 4 47 44 F g. 7 5/ A A -54 Q 556 v v 46 /n venfor E wa/o fioecklhg a Y HIS A T TORNEYS Patented Nov. 21, 1950 UNITED STATES ENT OFFER PAD ROLLER DEVICE FDR MOTION-PHCTURE 7 PROJECTING MACHINES Application April 19, 1946, Serial No. 663,429

9 Claims. 1

This invention relates to pad rollers for moving picture projecting machines and it is an object of this invention to provide such a projector with a pad roller device of improved construction which will facilitate the threading of the film in the machine, prevent improper engagement of the film with the film sprockets associated with the pad rollers and provide means for rapidly and positively ensuring the necessary extent of film slack to be left after the threading of the film for proper operation of the pro jector.

In the drawings:

Fig. 1 is a viewin side e1evation,partycut away, of a film gate and associated parts including pad rollers in accordance with this invention, the gate and pad rollers being shown in opened position for the threading of the film;

Figs. 2 and 3 are views similar to Fig. 1 with the film gate shown in closed position and with the pad rollers in position to measure the film slack loops in Fig. 2 and in operating positions in Fig. 3;

Figs. 4, 5 and 6 are views in side elevation of the lower pad roller device shown detached from the machine, the pad roller being shown in opened position for the threading of the film; in film loop measuring position; and in operating position, respectively;

Fig. '7 is a partial sectional view of the structure shown in Figs. 4, 5 and 6 taken as on line 1-7 of Fig. 6; and

Fig. 8 is a View in elevation, looking from the left in Fig. 4.

- In commercial motion picture projectors in which the film is advanced intermittently, it has been difficult to thread up the machine at the beginning of the film owing to the necessity of maintaining the film in contact with the various advancing sprockets while adjusting the film loops to the desired size and in proper registry.

In the drawings the invention is shown in con nection with a motion picture projector having a film gate I9 carrying lenses I2 and movably mounted on a bar ii, movement or" the film gate. IS on the bar H to facilitate threading of the film being controled by a suitable mechanism 13. As shown, the source of light is at the left and the screen at some distance to the right and the film gate has the usual projection aperture corresponding to the light aperture it. The film i4 is placed between the film gate it the pressure shoes i5 and light aperture it. The usual intermittent driving sprocket wheel i! has a film guiding roller [8 which is pivotally mounted at [9 below the film gate and a hol back roller and film registry means 23 is mounted on the usual plate 22 which carries the pressure shoes and on the opposite side of the'film It from the film gate ill. Above the film gate, and separate therefrom, is a film sprocket wheel '2! for advancing the film continuously to the film gate while below the film gate is the film sprocket wheel 22 which takes the film supplied intermittently by the sprocket wheel I! and delivers it continuously to the winding reel or sound producing apparatus.

Associated with the sprocket wheels is and 2! are pad roller devices of improved construction, each pad roller comprising a stripper mechanism 36 and roller means 32 rotatably mounted on a pin 34 fixed in a flanged sleeve 36 by a cotter pin 3?. The sleeve is inserted in an opening 38 formed in a boss 39 projecting from the projector frame or casing (not shown) and is secured in position by a set screw it! engaging in a groove i! in the outer surface of the sleeve 36. The roler means 32 comprises an arm l2 pivotally mounted at one end on the pin 35 and pro vided with spring pressed balls or detents 43 which engage in recesses in the flange of sleeve 35 and hold the arm 42 in adjusted position. At its other end the arm 42 is provided with an opening in which is mounted a pin it which projects to both sides of the arm 42 and has thereon at one side of the arm e2, pad rollers mount d on roller bearings 46 journaled onthe pin it and separated by one end of an arm 52 secured to the pin M by a cotter pin 48. The outer roller 55 is held in position on the pin it b a knob 49 secured to the pin 44 by a cotter pin 59. The pad rollers :35 are positioned to be aligned with the t:eth of the sprocket wheel and are formed with the usual grooves to receive the sprocket teeth and flanges at one side to serve as guides for the film on the sprocket.

To the pin 2-4 at the other side of the arm 52, a cotter pin 5! secures an arm 41, having one end beveled on both sides, as at 52a. and positioned so as to have the beveled faces engaged by a spring-pressed ball or detent 5t mounted in a lug or projection on the arm 52 and which serves to retain the arms 41 and 52 in adjusted position. The point of the bevel 52a can be considered as dead center for and unitary with the arm 52. The arm i? is also provided with a short pin which projects into a recess 55 formed in the arm 52 and limits the pivotal movement of the arms 4! and 52. At its outer end the arm 52 has fixed therein a pin on which 5 mounted a plurality of spaced rollers 53 shaped as are the rollers 45 to receive the sprocket wheel and guide the film thereon as do the rollers 45.

The stripper mounted on the pin 34 comprises a member having a tapered film engaging portion 30a which extends to a position closely adjacent the sprocket wheel and, in case of a break in the film, prevents the wrapping of the film on thesprocket. The stripper also has an operating handle portion 3% and, on one side, a recess 33c in which is mounted a spring,- pressed ball or detent 60 positioned to engage in recesses in the flange of a knob 62 fixed onthepin 34 by a cotter pin 64. The stripper 3B is separate from the pad roller support arm s2 permitting movement of the pad rollers 45 and the auxiliary pad rollers 58 away from. the sprocket Wheel to facilitate threading the film in the machine While the stripper 3B is left in its operative position to prevent the film being placed on the sprocket wheel improperly.

In threading film in a moving picture projector equipped with pad rollers in accordance with this invention, the pad roller arms 42 and 52 are rotated on their supportsto the positions shown in Figs. 1 and 4, the film gate is is moved to'the right on its support H, theroller it moved from the intermittent driving sprocket ii, the light of film registry means 23 isv lighted and a sufiicient length of film to reach the film take-up drum is drawn. The film is then placed around the upper driving sprocket 2i and over its pad rollers. 45, through the film gate 10,- loosely around the intermittent drive sprocket I! and around the lower drive sprocket 26 after passing below its pad rollers 45. The auxiliary pad rollerstzi of thelower and upper drive sprockets 20 and 2| are then engaged with the sprockets, as shown in Figs. 2 and 5, to keep the film alined in. its running course. The film is then registered with the film registry means. 23 and engaged with. the teeth of. the intermittent drive sprocket II, the sprocket l'lbeing at the end of a. movement. The roller Isis closed on the intermittent sprocket I 7 and the'film gate 19 is closed. The slack-loops in the film are then determined by drawing the film, gently over the pad rollers 45.and their associated sprockets 2! and 20 with the rollersfifi lifted from the sprockets. With the film drawn snug, the rollers 58 are first brought into contact with the sprockets 2|. and 20 by moving the arms 52 .and then rollers 45' are brought into contact with the sprockets 2|. and 20 by moving arms 42, the, detents 55 keeping the rollers 58in Contact with the sprockets as the rollers are engaged, the rollers 58 being moved from thepositions shown in Fig. 2 to the positions shown in Fig. 3. The film [4, when drawn snug on the rollers llfiand sprockets 2! and as has a position as shown in Fig. 2 but when the rolls are moved to engage the sprockets slack loops, as shown in Fig. 3, are left in the film, the length and position of the arms 42 being such that the slack loops are of the proper size for operation of the machine.

Whenever it is necessary to remove one of the sprockets the handle 35522 of the stripper is used to turn the stripper so that its film-engaging position 38a is out of overlapping relationship with the sprocket. Thenthe sprocket can be removed without dismantling the stripper.

What I claim is:

1. In a motion picture projector, a film-advancing sprocket, a pad roller for engaging said sprocket, a pivotally mounted arm for supporting said pad roller in a film and sprocket-engaging position, an auxiliaryroller for hold ng, film on said sprocket when said pad roller is spaced therefrom, and means pivotally supporting said auxiliary roller on the pad roller arm on an axis parallel to the sprocket axis, said auxiliary roller being adapted to have movement toward and from the sprocket independently of the pad roller.

2. In a motion. picture projector, a film-ad vancing sprocket, a pad roller for engaging said sprocket, a pivotally mounted arm for supporting said pad roller in a film and sprocket engaging position and a film-measuring position spaced from said sprocket, an auxiliary roller for holding film on said sprocket when said pad roller is spaced therefrom, and means pivotally supporting said auxiliary roller on the pad roller arm on an axis parallel to the sprocket axis, said auxiliary roller being adapted to have movement toward and from the sprocket independently of the pad roller.

3. A motion picture projector according to claim 1, in which the means supporting the auxiliary roller comprises a. second arm pivoted on the pad roller arm on an axis parallel to the sprocket axis'to carry the auxiliary roller, and there is a loop-measuring position for" the first pivotal arm whenthe padroller is spaced fromthe sprocket, and there are means adapted to hold the auxiliary roller in film-engaging-contact with the sprocket when thepad rolleris in loop-measuring position.

4. A motion picture projector according to claim 3 in which the means to; keeptheauxiliary roller in contact comprises resilient means tending to keep the auxiliary roller in filmeengaging contact with the sprocketw-hen the. pad rolleris both out of and film-engaging contact with the sprocket;

5. A motion picture projector according to claim 4 in which the resilient means is con-, nected at such points'with relation to the pivot point of the auxiliar roller asto permit the second arm to be swung away from the sprocket.

6,. A motion picture projector having a filmadvancing sprocket, a pad roller for engaging said sprocket, a pivotally'mounted arm for supporting said pad roller in a film and sprocketengaging position, an auxiliary roller for holding film on said sprocket when. said pad roller is spaced therefrom and a second arm carrying the auxiliary roller pivoted on the first arm onan axis parallel to the sprocket axis in combination with resilient means normally tending to keep the auxiliary roller in film-engaging contact with the sprocket when the pad roller is both out of and in film-engaging contact with the sprocket, said resilient means having a dead center beyond which it is adapted to hold the second arm away from the sprocket.

7. A motion picture projector according to claim 6 in which there is present in the resilient means a bevelled point unitary with the pivot end of the second arm. and spring means pressing on the point tending to keep the auxiliary roller in contact with the sprocket or swung away from it according to the, side of the point on which it is pressing.

8. In a motion picture projector according to claim 1, the provision of stripper means adapted to retain a position preventing application of the filmon the wrong side of the procket during threading up, said stripper means being pivotable out of such position independently of said two arms when it is desired to remove the sprocket.

2,530,448 5 6 9. In a motion picture projector according to REFERENCES CITED claim pivoting of the Stripper mealts on The following references are of record in the the same axxs as the pad roller arm, the stnpper file of this pamnt. means being adjacent the periphery of the sprocket on the side opposite the two rollers. 5 UNITED STATES PATENTS Number Name Date EWALD BOECKING- 1,957,164 Frappier et a1. May 1, 1934 2,073,225 Ross et a1 Mar. 9, 1937 

